Linear retractable seal valve

ABSTRACT

A linear retractable seal valve having an inlet and outlet port and a fluid passageway therebetween with a lateral passageway perpendicular to the fluid passageway and with a wedge sealing-slip assembly slideably held at opposite side edges of the wedge to two guide rails of the valve body and moveable from a distant valve open first location within the lateral passageway to a second location between inlet and outlet ports of the valve. The slip-wedge assembly has at least one closure slip with an inside face of the slip slideably engaging a tapering face of the wedge and with the slip at said second location being restrained from further longitudinal movement and moveable in a perpendicular direction of the longitudinal assembly movement into closure engagement with one of the valve ports. The guide rails are diametrically-opposed and extend longitudinally of the inside face of the lateral passageway into the fluid passageway. 
     At least one of the guide rails terminates at the second location on the inside wall of the fluid passageway with the end surface of the terminated rail providing a ramp. The wedge on at least one side edge thereof has a locking notch which extends in a transverse direction to the longitudinal assembly movement; this notch is in the side edge of the wedge which is adjacent the terminated rail. An actuating roller which is in engagement with a supporting surface of the slip is positioned to move into and out of the wedge notch at the second valve location; when the valve is in the locking notch of the wedge it engages the longitudinal edge of the adjacent guide rail and serves to lock the slip to the wedge, thereby precluding perpendicular movement of the slip during longitudinal passage of the assembly between the two valve locations. The roller, when in another position, unlocks the slip from the wedge by moving out of the locking notch and out of contact with the longitudinal edge of the rail and into engagement with the ramp at the end of the rail.

This invention relates to a gate type seal valve and more particularlyto a linear retractable seal valve having a body with an inlet andoutlet port and a fluid passageway therebetween in which a wedgesealing-slip assembly is moved from a distant first location of alateral passageway to a second location in the fluid passageway betweeninlet and outlet of the valve at which latter location the sealing slipsare wedged outwardly into closure engagement with the valve ports.

BACKGROUND OF THE INVENTION

The petroleum and refinery industries use a large number of gate valvesfor controlling flow of liquid and gas products. An earlier retractableseal gate valve is illustrated in U.S. Pat. No. 2,977,086, Heinen; thisvalve is closed by a sequential motion including a downward verticalmovement of a wedge-slip assembly through a lateral passageway to aposition in a fluid-passageway between inlet and outlet ports of thevalve, followed by a horizontal movement of the sealing slips intoengagement with the respective adjacent valve seats. The open positionis achieved by a reverse sequential movement, wherein the slips arefirst moved at a right angle away from the respective port seats andthereafter the wedge-slip assembly is moved in an upward verticaldirection through the lateral passageway away from the fluid passagewayof the valve.

Gate valves of this general type sometimes employ diametrically-opposedguide rails which extend longitudinally of the inside face of thelateral passageway with the wedge-slip assembly being moveably held bygrooves at opposite side edges of the wedge to the guide rails of thevalve body. Wedge-slip valves, perhaps because of their sequentialopening and closing motions and complexity of parts, require a stringentengineering design to assure reliability and trouble free operation.

SUMMARY OF THE INVENTION

The improved valve of the invention provides an efficient perpendicularpull-off of the sealing slips from the port seats of the valve withabsence of seal abrasion and wear. The structure of the inventionprovides positive locking of sealing slips away from the inner wall ofthe valve body while the wedge-slip assembly is being moved between openand closed valve positions; this is achieved by providing a rollermechanism which locks the sealing slips to the wedge during transport ofthe wedge-slip assembly between valve locations.

The linear retractable seal valve of the invention has a valve body withinlet and outlet ports and a fluid passageway therebetween and a lateralpassageway perpendicular to the fluid passageway. A wedge-slip assemblyis moveable longitudinally therein from a valve-open first locationwithin the lateral passageway to a distant second, valve-closed locationwhere the assembly is positioned in the fluid passageway between the twoports of the valve. The assembly has at least one closure slip, usuallytwo, with the inside face of the slip slideably engaging a tapering faceof the wedge. The slip is restrained at the second valve location fromfurther longitudinal movement and there is moveable in a perpendiculardirection of longitudinal assembly movement into closure engagement withan adjacent valve port. The valve of the invention has twodiametrically-opposed guide rails extending longitudinally of the insideface of the lateral passageway; the two rails continue from the lateralpassageway into the fluid passageway of the valve. The assembly ismoveably held by grooves at opposite side edges of the wedge to the twoguide rails of the valve body. At least one of the guide railsterminates (usually both in most embodiments of the valve) at the secondvalve location on the inside wall of the fluid passageway; the endsurface of the terminated rail provides a ramp. The wedge has a lockingnotch on at least one side edge thereof which notch extends in atransverse direction to the longitudinal assembly movement and isadjacent the terminated rail. A principle component of the valvelock-actuating mechanism is a roller which is parallel to the lockingnotch and in engagement with a supporting surface of the slip; theroller is positioned to move into and out of the notch at the secondvalve location. The roller, when in the locking notch of the wedge,engages the longitudinal edge of the adjacent guide rail and in thisposition serves to lock the slip to the wedge, thus precludingperpendicular movement of the slip during longitudinal movement of theassembly between the two valve locations. The roller unlocks the slipfrom the wedge by moving out of the locking notch and out of contactwith the longitudinal edge of the rail and into engagement with the rampat the end of the rail. During an initial step in the opening of thevalve, the roller in the latter position forestalls reverse longitudinalmovement of the slip until completion of full perpendiculardisengagement of slip from the adjacent valve port.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the valve of the invention detached fromfluid line;

FIGS. 1(a) and 1(b) are fragmentary cross-sectional views taken alongline 1(a)--1(a) of FIG. 1 providing details of alternative sealingelements;

FIG. 2 is an exploded view of critical elements of a preferred valve ofthe invention;

FIG. 3 is a longitudinal sectional view taken, partly in elevational,along line 3--3 of FIG. 1 showing the valve in its fully closed positionwith closure slips forced outwardly by a central wedge member intoengagement with inlet and outlet ports of the valve;

FIG. 4 is a partially cutaway elevational view in a plane perpendicularto that of FIG. 31 and with one of the closure slips removed to morefully illustrate the central wedge and its suspended lifting lug as wellas two spaced locking roller detent mechanisms;

FIG. 5 is a time sequential view to that of FIGS. 3 and 4 in opening ofthe valve showing the wedge member in a slightly elevated position withwedge locking groove approaching the level of the locking roller andwith the closure slips out of engagement with adjacent valve ports;

FIG. 6 is a sectional view in the same time instant as FIG. 5 but in aplane perpendicular to the latter figure showing the closure slipsmoving in perpendicular displacement away from the two ports of thevalve;

FIG. 7 is a sectional view later in time sequence to that of FIG. 5 withthe wedge at a somewhat more elevated position and with the wedgelocking notch in near alignment with the detent roller;

FIG. 8 is at the same instant as FIG. 7, but in a plane perpendicular tothe latter figure, showing the wedge lifting lug in initial engagementwith the two closure slips which slips are out of port closureengagement but still in alignment with the two ports of the valve;

FIG. 9 is a view in close time sequence to that of FIG. 7 showing theroller in the wedge locking notch after having just left the ramp at theterminal end of the adjacent guide rail and showing the closure slipcommencing to move in longitudinal displacement from previous alignmentwith the adjacent valve port;

FIG. 10 is a longitudinal sectional view, partly in elevational, inconsiderable later time sequence to that of FIG. 9 and in a planeperpendicular to the latter figure showing the closure slip-wedgeassembly in the valve full open position with the inlet and outlet portsof the valve clear to fluid flow;

FIG. 11 is a sectional view taken along line 11--11 of FIG. 10;

FIG. 12 is another embodiment of the valve of the invention having amoveable internal conduit segment which serves as the assembly liftinglug;

FIG. 13 is a fragmentary sectional view taken along line 13--13 of thevalve embodiment of FIG. 12;

FIG. 14 is a sectional view of still another embodiment of the valve ofthe invention which embodiment employs a single closure slip;

FIG. 15 is a fragmentary perspective detail view taken in area 15 ofFIG. 14 showing relationships of elements of the detent lockingmechanism with the valve in full port closure;

FIG. 16 is an exploded view of a portion of the elements of anotherversion of the valve of the invention;

FIG. 17 is a longitudinal sectional view of the valve of the alternativeembodiment of FIG. 16 showing the valve in its fully closed positionwith the closure slips forced outwardly by the central wedge member intoengagement with inlet and outlet ports of the valve;

FIG. 18 is an elevational view in a plane perpendicular to that of FIG.17 with one of the closure slips removed;

FIG. 19 is a longitudinal sectional view in considerable later timesequence to that of FIG. 18 showing the slip-wedge assembly in the valvefull-open position with the inlet and outlet ports of the valve open tofluid flow; and

FIG. 20 is a sectional view taken along line 20--20 of FIG. 19.

The linear retractable seal valve 20 of the drawings has a base body 22with aligned two ports 24, 25 and a fluid passageway 26 therebetween.The body 22 has a lateral passageway 28 perpendicular of the fluidpassageway 26 with a wedge-closure slip assembly 30 being disposed inthe latter passageway and moveable longitudinally therein from a firstvalve open position as shown in FIG. 10 where the assembly is positionedaway from the fluid passageway 26 to a spaced second valve closedlocation where the assembly 30 is positioned in the fluid passageway 26between the inlet and outlet ports 24, 25 of the valve as best seen inFIGS. 3 and 4.

The assembly 30 is made up of a central wedge member 32 which slideablycarries on its opposite tapered faces 33, 34 two closure slips 36, 38(see FIGS. 2 and 3). An elongated stem member 40 is held by adisconnectable T-coupling 42 (FIGS. 2 and 4) to the thick edge 44 of thewedge 32. The lateral passageway 28 of the valve body 22 is closed by abonnet 46 (FIG. 4) which has a necked-down portion 47 through which thestem member 40 extends. The bonnet 46 is fastened through an upperflange 48 to a lower flange 49 of a yoke member 50 through whichassemblage the stem 40 extends. The outer end 52 of the stem 40 isthreaded to engage a nut 53 and hand wheel 54, the turning of whichraises and lowers the stem member 40 and the wedge-slip assembly 30fastened thereto. As best seen in FIG. 3 the elongated stem member 40extends through a seat bushing 55 and a long packing 56 located in thenecked-down portion 47 of the bonnet 46. The packing 56 at its upper endengages a gland 58 (FIG. 3) clamped between the flange 48 of the bonnet46 and the flat plate 97 of the yoke 50.

The stem member 40 and hand wheel 54 provides means for moving thewedge-slip assembly 30 longitudinally of the lateral passageway 28.Means for moveably holding the wedge-slip assembly 30 to the valve body22 is provided by two diametrically-opposed guide rails 60, 61 (FIGS. 2and 4) which extend longitudinally of the inside face of the lateralpassageway 28. As seen in FIG. 4, the guide rails 60, 61 terminate atthe second location of the assembly on the inside wall of the fluidpassageways 26. The end surfaces of the terminated rails 60, 61 aresloped to provide ramps 64, the purpose of which will be describedlater. The wedge-slip assembly 30 is moveably held to the valve body 22(FIG. 2) by grooves 66, 67 in the side edges of the wedge whichslideably engage the opposing guide rails 60, 61. It will be seen thatthe two guide rails 60, 61 lie in a plane paralleling the spaced inletand outlet ports 24, 25 of the valve.

With reference to FIGS. 2 and 3, it will be seen that the closure slips36, 38 are slideably held respectively to the adjacent tapering faces33, 34 of the wedge member 32 by dove tail connections 68, 69. Theclosure slips 36, 38 (see FIGS. 2 and 3) have on their respective insidefaces adjacent their outer edges two spaced lugs which extendperpendicularly of direction of longitudinal movement of the assemblywith the two lugs 37 of slip 36 overlying lugs 39 of slip 38. Theseveral lugs 37, 39 of the two slips 36, 38, each arises from a flat,vertical area 47 of its respective slip. Use of the overlying lugstructural arrangement to tie the two slips together synchronize theirlongitudinal movement between closed and open positions of the valve;this direct contact structural arrangement precludes unsymmetricalmovement of the slips which might occur with use of an interveningelement for synchronizing purposes. The opposite side edges of the wedge32 are cutaway at its thin edge as best seen in FIG. 2, to provideunencumbered space into which the respective lugs 37, 39 of the twoslips 36, 38 may extend without engaging the interposed wedge 32. Theunencumbered upper surfaces of the two overlying lugs 37 of the lefthand slip 38 provide rolling supportive surfaces for rollers 73. Therollers 73 are usually circular but may be polygonal in cross section.The wedge 32 adjacent its thin edge has spaced locking notches 76 in itsopposite side edges which notches extend the thickness of the wedge andopen respectively toward one or the other of the adjacent rails 60, 61.Each of the rollers 73 has a first valve-open position wherein theroller occupies the associated locking notch 76 of the wedge andcontacts the longitudinal edge of the adjacent guide rail. Thisrelationship of elements in the first roller position provides means forlocking the wedge 32 and slips 36, 38 together for longitudinal movementbetween the first assembly (valve open) position of FIG. 11 and thesecond assembly (valve close) position of FIG. 3. In the second,valve-closed roller position the respective rollers 73 have moved out oftheir locking notches 76 and out of contact with the longitudinal edgesof the adjacent one of the two rails 60, 61. In moving between the tworoller positions, each roller 73 contacts the sloping ramp 64 at the endof the adjacent guide rail.

In closing the valve 20, the wedge slip assembly 30 is moved from itsopen first location of FIG. 11 within the lateral passageway 28 to aspaced second location, that of FIG. 4, where the assembly is disposedin the fluid passageway 26 between the inlet and outlet ports of thevalve. Means are provided at this second location for stoppinglongitudinal movement of the two closure slips 36, 38 when therespective slips are in alignment with the two ports 24, 25 whilepermitting further longitudinal movement of the wedge 32; this isaccomplished by spaced stop pins 78, 79 (FIG. 4) that extend through thewall of the body 22 into engagement with the underside of the respectivetwo slips. Remembering that the two closure slips 36, 38 (FIG. 2) areslideably held to the opposite tapering faces 33, 34 of the wedge 32, itwill be understood that further longitudinal movement of the wedgepromotes perpendicular outward movement of the respective stopped slipsinto closure engagement with the adjacent ports 24, 25.

In opening of the valve there is a reverse longitudinal movement of thewedge in an upward direction. There is with the turning of the handwheel to open a closed valve, an initial movement of the two closureslips 36, 38 (see FIG. 6) in a perpendicular inward direction out ofengagement with the adjacent ports 24, 25. It will be appreciated thatbecause of this perpendicular disengagement of slips and ports, abrasivedamage of seals 80, 81 (FIGS. 1a, 1b and 2) of the slips 36, 38 isavoided. No longitudinal movement (i.e. in a vertical direction) of thetwo closure slips 36, 38 occurs during this initial opening step eventhough the wedge 32 itself is being moved upwardly by the stem member40. Upward longitudinal movement of the closure slips from the valve'sclosed position is dependent upon engagement of the underside of atleast the right hand slip 38 by a spaced rectangular lifting lug 84(FIGS. 2 and 8) suspended from the thin edge of the wedge 32. Thelifting lug 84 must engage the underside of the slip having the twolower lugs 39 which lower lugs 39, in turn, support the overlying twolugs 37 of the other slip. In the design of the illustrated valve, thelifting lug 84 in actuality contacts the undersurface of both slips 36,38.

The length of longitudinal movement in an upward direction of the wedge32 from the valve's closed position independent of the two slips isdetermined by the length of lifting lug hanger 86 (see FIG. 3). When thelifting lug 84 first engages the underside of the closure slips 36, 38as seen in FIG. 8, the initial phase of the valve opening is completedand upward movement of the two slips with the wedge then commences.Prior to this time, the slips will have been only moved in aperpendicular inward direction out of contact with the adjacent twoports 24, 25 by the upward longitudinal movement of the wedge 32.

The valve structure is designed to forestall premature upward movementof the two slips 36, 38 which may tend to occur due to a draggingfrictional effect in the initial opening phase with the wedge commencingits upward movement. As best seen in FIG. 4 during this initial openingmovement, the two slips are constrained from vertical motion by the tworollers 73 which are respectively lodged in confinement pockets providedby the upper surfaces of the upper lugs 39, the ramps 64 and shortvertical surfaces 96 of the wedge immediately above the locking notches76. When the lifting lug 84 in FIG. 8 engages the two slips 36, 38, theinitial phase of the valve opening movement is completed as the twoslips have moved inwardly out of engagement with their respective ports;at this time the respective two locking notches 76 of the wedge are insubstantial alignment with the adjacent rollers 73 and furtherapplication of force by the lifting lug 84 causes the rollers 73 toovercome friction and move into their associated notches as illustratedin FIG. 9; at which time the closure slips are then fixed to the wedgeand the assembly of slips and wedge may be moved to the full openposition of the valve illustrated in FIGS. 10 and 11.

Thus, it is seen that the rollers 73 serve in two functions: a firstfunction of locking the respective slips 36, 38 to the wedge 32 duringdownward movement of the wedge-slip assembly away from its open positionof FIGS. 10 and 11, this forestalls premature outward movement of theslips; and a second function during the initial phase of the valveopening wherein the rollers forestall premature upward movement of therespective slips while permitting their perpendicular disengagement ofthe adjacent ports.

Referring to FIGS. 1a and 2, it will be seen that the seals 80, 81 arecircular in configuration and held to the outside faces of therespective closure slips 36, 38 by seal retainer rings 82, 83. The twoseal retainers 82, 83 are removably held by several spaced screws to theexterior faces of the two slips 36, 38. Another sealing arrangement isshown in FIG. 1b.

With downward longitudinal movement of the assembly 30 away from itsfirst (valve open) location within the lateral passageway (FIGS. 10 and11), there would be danger but for the roller detent arrangement ofpremature movement of the two closure slips 36, 38 into engagement withthe walls of the passageway. The locking of the two closure slips 36, 38to the wedge 32 via the two rollers 73, the locking notches 76 and thelongitudinal edges of the guide rails 60, 61 assures that there will beno untimely contacting of the passageway walls by the descending closureslips 36, 38 during movement of the assembly 30 from its first locationwithin the lateral passageway 28 to the second location within the fluidpassageway 26. When the closure slips 36, 38 engage two stop pins 78,79, the two slips 36, 38 are then in alignment with their adjacent valveports 24, 25 and the two rollers 73 move out of their respective lockingnotches 76 of the wedge 32. In moving into this valve-closed positionthe rollers 73 escape from the longitudinal edges of the adjacent rails60, 61 and move in contact with the ramps 64 along the unencumberedsurfaces of two slip lugs 37.

With reference to FIGS. 3 and 4 it will be seen that while the guiderails 60, 61 terminate at the second assembly location, the two rails docommence again and extend into a second lateral passageway 87 of thevalve. The second lateral passageway 87 is opposite in direction to thefirst 28, but in alignment therewith. Provision is made whereby thelifting lug 84 is moveably held by groove elements 89 at its oppositeends to the extended guide rails of the second lateral passageway 87.This feature of slideably holding the lifting lug 84 to the extended twoguide rails gives added stability to movement of the slip-wedge assembly30.

In the illustrated preferred embodiment of the valve a locking detentmechanism employing a roller 73 and associated locking notch 76 islocated at both side edges of the wedge 32. In a less rugged, smallerversion of the valve, a single roller 73 (and associated locking notch)is employed; in this version of the valve only one of the two guiderails needs to terminate at the second valve location.

In FIG. 2 the lifting lug 84 is shown with an optional stabilizingfeature which comprises a pair of spaced dowel pins 90 adjacent one edgeof the lifting lug. The illustrated two dowel pins 90 are oriented tofit into aligned holes 91 in the underside of the slip 38 when thelifting lug engages the slip in upward motion of the assembly 30.Similarly, the other side of the lifting lug 84 will be provided withlike spaced dowel pins to engage the other slip 36; the latter two dowelpins are not illustrated in FIG. 2 to minimize cluttering of thedrawing. The lifting lug 84 is fastened to the hangers 86 of the wedge32 by screws 93.

Another embodiment of the valve of the invention is illustrated in FIGS.12-13. In this arrangement an internally-situated conduit segment 88serves as the lifting lug 84 of the earlier described valve and issupported at the underside of the wedge 32. When the valve is in openposition the conduit segment 88 directly connects the inlet and outletports 24, 25 providing a confined stream flow therebetween. It will beseen in FIG. 12 that the usual flat enclosure plate at the underside ofthe valve body is replaced with a bell shape member 92 of adequatevolume to receive the conduit segment 88 in the valve-closed position.

A third embodiment of the valve of the invention is illustrated in FIG.14; this valve employs a single closure slip which closes only one ofthe two valve ports; this is a desirable feature in some chemicalmanufacture where it is important to avoid entrapment of liquid in thespace between the two valve ports 24, 25 during valve closure. It willbe remembered that the cylindrical locking rollers 73 are on theunobstructed upper surfaces of the two spaced lugs of the slip 38.Because only one slip is employed in this embodiment of FIG. 14, it isnecessary to provide a closure 95 fastened to the wedge 32 to avoidaxial movement of the rollers 73. The fragmentary view of FIG. 15 aptlyillustrates the relative positions of each roller 73 and the supportinglug during valve closure; in this position it is seen that the rollerhas left the locking notch 76 of the wedge 32 and engages the shortvertical surface 96 of the wedge immediately adjacent the locking notch.FIG. 15 is illustrative of the mechanism of the valve of FIGS. 3-11 aswell as that of FIG. 14.

The design of the invention provides for easy access to the interior ofthe valve, from either above or below, without the valve's removal fromthe fluid line in which it is installed. This is a particularlydesirable feature for replacement of the resilient seal; this isaccomplished by first removal of a bottom closure plate 94 (see FIG. 4)and then removal of stop pins 78, 79. It will be recalled that normally,the stop pins 78, 79 limit longitudinal movement of the closure slips36, 38; however, with the removal of the stop pins it is then possibleto pass the slips beyond their usual stopped position and remove theslips from the valve for repair. Replacement of the resilient seals 80,81 is then readily accomplished by removal of the retainer rings 82, 83of closure slips 36, 38 (FIG. 2). The resilient seal 80 of FIG. 1b iscast and molded in place; a chemical solvent is employed to remove aworn seal.

In the various embodiments of the valve illustrated in FIGS. 1-15, theroller has for its supporting surface a lug found on the inside face ofa single slip. In the instance of the valve having two slips (FIGS. 2,3)a single lug provides the supporting surface for the roller and this lugoverlies a cooperating lug of the other slip; this lug overlyingarrangement assures that the two slips move together in an upwarddirection. The version of the valve illustrated in FIGS. 16-20 dividesthe direct supporting surface for the roller 73 between the two slipswith the roller being carried at its opposite ends by ledges (lugs) 100,101 on the inside faces of the respective two slips 36, 38. Theoperative surfaces of the ledges 100, 101 of the two slips 36, 38supporting the roller 73 lie in a common plane perpendicular todirection of longitudinal movement of the wedgeslip assembly. Withescape of the roller into contact with the ramp 74 in closing of thevalve and simultaneous engagement of the underside of the slips 36, 38by the stop 78, 79, further longitudinal movement downwardly of thewedge 38 causing the two slips 36, 38 to move into closure engagementwith the adjacent valve ports as illustrated in FIGS. 17, 18. In openingthe valve from the closed position of FIGS. 17 and 18, the wedge 32commences its upper movement without the two slips 36, 38 which areprecluded from upward motion at the outset by the roller 73 whichengages the ramp 64. When the locking notch 76 has moved into alignmentwith the roller 73 application of additional upward force to the wedge32 causes the roller 73 to move into the notch 76; thereafter thewedge-slip assembly is moved in a unit in an upward direction towardsthe full valve open position of FIGS. 19 and 20.

It will be seen that in the version of the valve of FIGS. 16-20 that asingle roller is utilized; it will be appreciated that in someembodiments it will be desirable to employ a roller on each side edge ofthe wedge. A two roller arrangement gives added stability to the valveand will normally be used in larger versions of the valve. Thesupportive ledge concept of FIGS. 16-20 is adaptable to the single slipversion of the valve of FIG. 14; in which application one end of theroller will be supported by a ledge of closure 95 (see FIG. 14) with theother end of the roller being supported by the ledge 101 of slip 38.

The valve of the embodiments of FIGS. 15-20 differs from the earlierdescribed embodiments of the valve of the invention in having a liftinglug 84 which necessarily engages the underside of both slips 36, 38 inmoving the wedge-slip assembly towards the valve open position; in theearlier illustrated versions of the valve there is employed anarrangement wherein a lug of one slip overlies that of the other whicharrangement provides synchronization of the slips. In the instantversion the simultaneous engagement of the underside of the two ledges36, 38 by the lifting lug 84 provides the simultaneous upward motion ofthe ledges of the two slips.

Various modifications may suggest themselves to those skilled in the artwithout departing from the spirit of our invention, and, hence, we donot wish to be restricted to the specific form shown or uses mentioned,except to the extent indicated in the appended claims.

It is claimed:
 1. In a linear retractable seal valve having a body withan inlet and outlet port and a fluid passageway therebetween, said bodyhaving a lateral passageway perpendicular to the fluid passageway with awedge-slip assembly moveable longitudinally therein from a valve openfirst location within the lateral passageway to a distant secondlocation where the assembly is positioned in the fluid passage-waybetween the two ports of the valve, said assembly having at least oneclosure slip with an inside face of the slip slideably enaging atapering face of the wedge and with the slip at second location beingrestrained from further longitudinal movement and moveable in aperpendicular direction of the longitudinal assembly movement intoclosure engagement with one of the valve ports, twodiametrically-opposed guide rails extending longitudinally of the insideface of the lateral passageway and into the fluid passageway, saidassembly being moveably held by grooves at opposite side edges of thewedge to the guide rails of the valve body, said guide rails lying in aplane paralleling the two valve ports, with the valve being returned toits open position through a reverse sequential movement, theimprovement:wherein at least one of said rails terminates at the secondlocation on the inside wall of the fluid passageway and with the endsurface of the terminated rail providing a ramp; said wedge on at leastone side edge thereof having a locking notch extending in a transversedirection to the longitudinal assembly movement, said notch being in theside edge of the wedge adjacent the terminated rail; a roller parallelto the locking notch in engagement with a supporting surface of the slipand positioned to move into and out of the notch at the second valvelocation, said roller when in the locking notch of the wedge and inengagement with the longitudinal edge of the adjacent guide rail servingto lock the slip to the wedge, thus precluding perpendicular movement ofthe slip during longitudinal movement of the assembly between the twovalve locations, said roller in one of its positions unlocks the slipfrom the wedge by moving out of the locking notch and out of contactwith the longitudinal edge of the rail and into engagement with the rampat the end of said rail.
 2. A valve in accordance with claim 1 whereinthe groove stops short of the locking notch, with said notch being setinwardly of the groove and adjacent the thin edge of the wedge.
 3. Avalve in accordance with claim 1 wherein the wedge-slip assembly has twoslips held respectively to the opposite tapering faces of the wedge withthe roller being supported at its ends by ledges on the inside faces ofthe respective two slips.
 4. In a linear retractable seal valve having abody with an inlet and an outlet port and a fluid passage-waytherebetween, said body having a lateral passageway perpendicular to thefluid passageway with a wedge-slip assembly moveable longitudinallytherein from a valve open first location within the lateral passagewayto a distant second location where the assembly is positioned in thefluid passageway between the two ports of the valve, said assemblyhaving at least one closure slip with an inside face of the slipslideably engaging a tapering face of the wedge and with the slip atsaid second location being restrained from further longitudinal movementand moveable in a perpendicular direction of the longitudinal assemblymovement into closure engagement with one of the valve ports, twodiametrically-opposed guide rails extending longitudinally of the insideface of the lateral passageway and into the fluid passageway, saidassembly being moveably held by grooves at opposite side edges of thewedge to the guide rails of the valve body, said guide rails lying in aplane paralleling the two valve ports, with the valve being returned toits open position through a reverse sequential movement, theimprovement:wherein at least one of said rails terminates at the secondlocation on the inside wall of the fluid passageway and with the endsurface of the terminated rail providing a ramp; said wedge on at leastone side edge thereof having a locking notch extending in a transversedirection to the longitudinal assembly movement, said notch being in theside edge of the wedge adjacent the terminated rail; a roller inengagement with a supporting surface of the slip, said roller having afirst position wherein the roller is constrained to the locking notch ofthe wedge when in engagement with the longitudinal edge of said one ofthe guide rails, and a second position wherein the roller has moved outof the locking notch of the wedge and out of contact with thelongitudinal edge of said rail and into engagement with the ramp at theend of the rail; said roller in its first position acting to lock theslip to the wedge, thus forestalling perpendicular movement of the slipduring longitudinal movement of the assembly between first and secondlocations; and said roller in its second position acting to forestallreverse longitudinal movement of the slip during opening of valve untilcompletion of perpendicular disengagement of slip and adjacent valveport.
 5. A valve in accordance with claim 4 wherein the groove stopsshort of the locking notch, with said notch being set inwardly of thegroove and adjacent the thin edge of the wedge.
 6. A valve in accordancewith claim 4 wherein the roller in its second position is in engagementwith the ramp and a flat surface of the side edge of the wedge, saidflat surface being parallel to the guide rails and immediately adjacentthe locking notch.
 7. A valve in accordance with claim 4 wherein thewedge-slip assembly has two slips which are held to opposite taperingfaces of the wedge and the supporting surface for the roller is sharedbetween the two slips with the roller at its opposite ends engagingseparate supporting planes of the respective two slips.
 8. In a linearretractable seal valve having a body with an inlet and outlet port and afluid passageway therebetween, said body having a lateral passagewayperpendicular to the fluid passageway with a wedge-slip assemblymoveable longitudinally therein from a valve open first location withinthe lateral passageway to a distant second location where the assemblyis positioned in the fluid passageway between the two ports of thevalve, said assembly having two closure slips with their respectiveinside faces slideably engaging separate tapering faces on the wedgelocated therebetween and with the two slips at said second locationbeing restrained from further longitudinal movement and moveable in aperpendicular direction of the longitudinal assembly movement intoclosure engagement with the inlet and outlet valve ports respectively,two diametrically-opposed guide rails extending longitudinally of theinside face of the lateral passageway and into the fluid passageway,said assembly being moveably held by grooves at opposite side edges ofthe wedge to the guide rails of the valve body, said guide rails lyingin a plane paralleling the two valve ports, with the valve beingreturned to its open position through a reverse sequential movementwherein the two slips are moved in a perpendicular direction out ofclosure engagement with the respective valve ports before commencingreverse longitudinal movement of the wedge-slip assembly away from thesecond valve location toward the first location, the improvement:whereinat least one of the rails terminates at the second location on theinside wall of the fluid passageway with the end surface of theterminated rail providing a ramp; said wedge having a locking notch onone of its side edges extending in a transverse direction to thelongitudinal assembly movement; a roller extending between the slips andassociated with the notch of the wedge and adapted for movement into andout of the notch, said roller having a first and second position; saidroller in the first position being constrained to the locking notch ofthe wedge when in engagement with the longitudinal edge of the adjacentguide rail, said roller in the first position acting to lock the slipsto the wedge, thus forestalling perpendicular movement of the slipsduring longitudinal movement of the assembly between first and secondvalve locations; said roller in the second position having moved out ofthe locking notch of the wedge and out of contact with the longitudinaledge of the adjacent rail and into engagement with the ramp at the endof said rail, said roller in the second position during opening of thevalve acting to forestall reverse longitudinal movement of the slipsuntil completion of perpendicular disengagement of slips from theadjacent valve ports.
 9. A valve in accordance with claim 8 wherein thewedge groove stops short of the locking notch with the locking notchbeing set inwardly of the groove and adjacent the thin edge of thewedge.
 10. A valve in accordance with claim 8 wherein the roller in itssecond position is in engagement with the ramp of the adjacent rail anda flat surface of the side edge of the wedge, said flat surface beingparallel to the guide rail and immediately adjacent the locking notch.11. A valve in accordance with claim 8 wherein the roller is supportedat its opposite ends by ledges on the inside faces of the respective twoslips.